# Play Contexts and Generic Prisoner’s Dilemma¶

There are four possible round outcomes:

• Mutual cooperation: $$(C, C)$$
• Defection: $$(C, D)$$ or $$(D, C)$$
• Mutual defection: $$(D, D)$$

Each of these corresponds to one particular set of payoffs in the following generic Prisoner’s dilemma:

Cooperate Defect
Cooperate (R,R) (S,T)
Defect (T,S) (P,P)

For the above to constitute a Prisoner’s dilemma, the following must hold: $$T>R>P>S$$.

These payoffs are commonly referred to as:

• $$R$$: the Reward payoff (default value in the library: 3)
• $$P$$: the Punishment payoff (default value in the library: 1)
• $$S$$: the Sucker payoff (default value in the library: 0)
• $$T$$: the Temptation payoff (default value in the library: 5)

A particular Prisoner’s Dilemma is often described by the 4-tuple: $$(R, P, S, T)$$:

>>> import axelrod
>>> axelrod.game.DefaultGame.RPST()
(3, 1, 0, 5)